Air Source Heat Pumps
A heat pump is an energy-efficient, low-carbon heating system that uses renewable energy from the air, ground, or water to heat your home or business. Unlike traditional gas or oil boilers that generate heat by burning fuel, heat pumps transfer existing heat from the environment, making them one of the most efficient and environmentally friendly heating solutions available.
Air source heat pumps absorb heat from the outside air, while ground source heat pumps extract heat from the earth. This heat is then upgraded and circulated through your radiators, underfloor heating, and hot water system to provide consistent, comfortable warmth all year round — even in cold weather.
Because heat pumps use electricity to move heat rather than create it, they can deliver significantly more energy than they consume, helping to reduce energy bills and carbon emissions. As a result, heat pumps are becoming a popular choice for homeowners and businesses looking to switch to renewable heating, improve energy efficiency, and future-proof their property.
Key benefits of a heat pump
Lower Energy Bills
Heat pumps are highly energy efficient because they transfer heat rather than generate it. This means they can produce more heat energy than the electricity they use, helping to significantly reduce heating costs compared to traditional gas or oil systems.
Reduced Carbon Emissions
By using renewable energy from the air or ground, heat pumps dramatically cut your property's carbon footprint. This makes them an ideal solution for homeowners and businesses looking to switch to low-carbon heating and meet future environmental standards.
Low Maintenance and Long Lifespan
Heat pumps have fewer moving parts than combustion boilers, resulting in lower maintenance requirements and a long operational life — often 15 to 20 years or more.
Improved Energy Efficiency Rating
Installing a heat pump can improve your property's Energy Performance Certificate (EPC) rating, making it more attractive to buyers, tenants, and investors.
Future-Proof Heating Solution
As the UK moves away from fossil fuel heating, heat pumps are becoming the preferred alternative. Installing one now helps future-proof your property against changing regulations and rising fuel costs.
Potential Government Incentives
Financial incentives and grants may be available to support heat pump installation, helping reduce upfront costs and accelerate your return on investment.
Heating and Hot Water from One System
A heat pump can supply your central heating and domestic hot water, replacing traditional boilers with a single, energy-efficient solution.
Why Choose an Air Source Heat Pump?
An air source heat pump is a highly efficient, renewable heating system that provides reliable heating and hot water while significantly reducing energy bills and carbon emissions. By extracting heat from the outside air — even in cold weather — air source heat pumps typically achieve efficiencies of 300–400%, meaning they produce 3 to 4 units of heat for every unit of electricity used. In comparison, modern gas boilers are usually around 90–94% efficient, as they can only generate heat from the fuel they burn. This makes air source heat pumps one of the most energy-efficient heating solutions available for homes and businesses.
Source: Energy Saving Trust
They are also easier and less disruptive to install than ground source systems, making them an ideal choice for properties upgrading from traditional gas or oil boilers to modern renewable heating. With lower running costs, minimal maintenance, and eligibility for the £7,500 Boiler Upgrade Scheme grant, air source heat pumps offer a future-proof solution that improves energy efficiency, supports sustainability goals, and adds long-term value to your property. Pairing a heat pump with solar panels lets you run it on electricity you generate yourself, and we regularly fit heat pumps as retrofits in existing homes.
How does an air source heat pump work?
An Air Source Heat Pump works like a fridge in reverse. It takes energy from the air around you and, using a system of heat exchangers and compressors with a refrigerant, it multiplies this up to heat enough hot water for your heating systems and hot water taps.
Step by step process
Air is pulled over a series of fine coils by a finely balanced fan unit. The coils contain a liquid refrigerant which absorbs the heat from the air. The refrigerant boils at -24°C so, even if the air outside has dropped below -10°C during a cold snap, it will still be warm enough to make the refrigerant boil.
The vaporised refrigerant is compacted using a compressor. This creates hot gas, up to 100°C, which is used to heat the water contained in the thermal store via a heat exchanger.
The air source heat pump continues to work in this way until the water in the thermal store hits the temperature required for the radiators and hot water required. The fan unit then switches off until the temperature of the thermal store falls and needs recharging again.
The efficiency of an air source heat pump varies as the outside temperature changes. Overall, we would expect most systems to generate 3.5kW of heat for every 1kW of electricity used, creating an average Coefficient of Performance (COP) of 3.5, indicating that they deliver 3.5 times more thermal energy than they consume in terms of electrical energy.
Ground Source Heat Pumps
Ground source heat pumps extract heat from the ground using buried pipes, typically in your garden. The pump circulates a mixture of water and antifreeze around a loop of pipe, called a ground loop. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump.
Even in winter the ground stays at a constant temperature under the surface, so the heat pump can be used throughout the year. The length of the ground loop depends on the size of your plot and the amount of heat required to heat your home.
This heat can be used to heat radiators, underfloor or warm air heating systems and the hot water in your home all year round.
Key benefits of a ground source heat pump
Lower Fuel Bills
It could lower your fuel bills, especially if you replace conventional electric heating.
Heating and Hot Water
Can be used in the production of both heating and hot water from a single system.
Year-Round Efficiency
Provides good levels of efficiency all year round, even in the depth of winter.
Long Lifespan
Lasts up to three times longer than a conventional boiler installation.
Low Maintenance
Designed to be incredibly low maintenance with minimal servicing required.
Nothing Visible Outside
Nothing visible from the outside of your property, preserving your home's appearance.
How does a ground source heat pump work?
A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe, called a ground loop, which is buried in your garden. The heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump.
The four key elements
The collector loop is placed under the ground in a parallel array, similar to an underfloor heating system, or via a vertical bore. A mixture of water and antifreeze is pumped through this. As the liquid flows through the underground pipes, it picks up the temperature of the earth around it, typically returning to the heat pump at about 6°C.
Once back at the heat pump, the liquid is passed against a heat exchanger. On the other side of the heat exchanger is a refrigerant. This refrigerant boils at -24°C, so 6°C is plenty to make it boil rigorously.
The now gaseous refrigerant is squashed back down using a compressor. Whenever you squash a gas you force it to release energy.
The released energy is passed into a thermal store, causing the water to get hotter. The cycle continues until the water hits the temperature required to heat your radiators and hot water.
Heat Pump FAQs
Is my home suitable for a heat pump?
Most homes can run well on a heat pump when the system is designed properly. We carry out a room-by-room heat loss calculation to size the heat pump correctly and check whether any radiators need upgrading to suit the lower flow temperatures heat pumps work at.
Can I get a grant for a heat pump?
Homes in England and Wales can get £7,500 off an air source or ground source heat pump through the government's Boiler Upgrade Scheme, plus an extra £1,500 until March 2027 if the property is currently heated by oil or LPG and has no mains gas. The grant is applied for by your MCS-certified installer and taken off the price you pay.
Is there VAT on a heat pump installation?
The supply and installation of air source and ground source heat pumps in homes is zero-rated for VAT until 31 March 2027. After that the reduced rate of 5% is due to apply.
Do air source heat pumps work in cold weather?
Yes. The refrigerant inside boils at around -24°C, so an air source heat pump keeps extracting heat from the outside air even when it is well below freezing. Efficiency does dip in very cold weather, which is why correct sizing matters.
How long does a heat pump last?
Heat pumps have fewer moving parts than a combustion boiler and typically last 15 to 20 years or more with regular servicing. Ground source systems often last longer still.
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The installation process
Solwat provides a complete end-to-end heat pump installation service.
Initial Consultation
We discuss your requirements and assess whether a heat pump is right for your property.
Survey & Design
A detailed site survey and heat loss calculation ensures the system is correctly sized for maximum efficiency.
Professional Installation
Our MCS-accredited engineers install your heat pump with minimal disruption.
Commissioning
We thoroughly test and commission the system to ensure it's performing at its best.
Aftercare & Support
Ongoing support and maintenance to keep your system running efficiently for years to come.
Ready to get started?
Get in touch for a free, no-obligation quote. Our team will assess your property and recommend the best solution.
Get in ContactSolwat Green Energy
Lea Green Farm, Christchurch Road, Lymington, Hampshire SO41 0LA
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